If you are not a carnivore and landed in the US of A, finding out that this made eating out quite challenging probably did not take too long. As time went by, you've also (hopefully) figured out that "vegetarian" may not always imply the absence of animal tissue (exhibit A: "vegetarian beef"). You have also realised that sometimes the presence of meat is implied in the name or type of dish (exhibit B: eggs benedict; exhibit C: a burger). If you have not capitulated yet, rest assured. If you are lucky enough to live in a city whose denizens have a penchant for eating out, you are likely to benefit from the variety of cuisine offered by various eateries, both independent and chain. Sprawlopolis, GA, for example, offers several choices.
Indian restaurants have always been a safe bet. Any of those who genuflect to the udipi or sarvana calling will guarantee a menu free of all carnal pleasures (no pun intended). Even those that offer non-vegetarian items can be relied upon to do justice to paneer, paalak, chanaa and lentils. Thai restaurants are tricky: you have to be sure that your "vegetarian soup" does not contain "fish sauce" (an ingredient that is perhaps as much a staple as wine in French cuisine). Burger joints are best avoided as are some casual dining chains whose vegetarian fare is an insult (exhibit D: T. G. I. Friday's). Mex-Mex and Tex-Mex restaurants fare marginally better, but it often seems like they make up for the absence of meat with bland frijoles and generous cheese.
This leaves us with some other chains that do rather well with meatless offerings. California Pizza Kitchen has an interesting array of pizzas, each marked by interesting combinations of ingredients. Several of these pizzas are vegetarian by design (with an extra charge for adding some form of meat) and some even have a vegetarian alternative at no extra price. You can also ask them to skip the meat if it's one of the ingredients.
I was surprised to have not noticed Mellow Mushroom's vegetarian options. There was always the possibility of substituting chicken with tofu in the hoagies and the standard Cheese pizza exists for vegetarians, but I had never quite noticed things like the Magical Mystery Tour, Gourmet White, Mega Veggie or the Kosmic Karma, both of which make vegetarians feel at home instead of n-class citizens who have to suffer tasteless fare while their chomp on animal protein.
Even though you could have choose not to have your hash browns at Waffle House without the ham or the chili, you would be well advised to note that everything gets cooked on the same grill. This means that, technically, there could be some animal fat in that otherwise tasy order of scattered, smothered and peppered hash browns.
Breakfast/brunch chains like The Flying Biscuit and J. Christopher's are safe places to catch a vegetarian bite (I just wish such places would not charge you extra for egg whites). The Flying Biscuit wins over J Christopher's for the presence of tofu and soysages on its menu.
Cafe Sunflower is a great place to dine at, if you want to give your brain a rest, order anything on the menu (because everything is vegetarian) and don't mind coughing up a few extra dead presidents for it. Getting to the branch at the intersection of Roswell and Hammond can be a challenge since it's a cramped intersection teeming with cars and the occasional MARTA bus, but if you're lucky, a trip on the weekend will be peaceful.
It has been a long long time since I ate at R. Thomas, but it's hard to beat (or miss) this unique funky independent eatery that was the first place I had seen a menu with the word "vegan" on it.